3.8 Malabsorption
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Recognise the clinical features of malabsorption
Tiredness / malaise (associated with anaemia)
Diarrhoea
Steattorhoea
Abdominal discomfort
Back pain should guide towards
Bloating
chronic pancreatitis.
Weight loss
Mouth ulcers / angular stomatitis
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Recognise chronic pancreatitis as a cause of malabsorption and abdominal back pain.
Chronic pancreatitis is mostly (60-80%) caused by alcohol abuse. Other causes include cystic
fibrosis (almost 100% of patients have chronic pancreatitis) and, rarely, hereditary in an
autosomal dominant pattern with variable penetrance.
Background box: For absorption of nutrients to take place, food must first be broken down
into nutrients and then these nutrients must be taken up. This two-phase approach is moderated
largely by two organs:
Breakdown into absorbable nutrients is achieved mostly by the pancreatic enzymes – these
include proteases, lipases and carboxylases.*
Uptake of nutrients occurs largely in the small bowel.
Hence diseases of the small bowel and pancreas both have the capacity to result in
malabsorption.
*
Mastication, stomach acid and bile are also important.
Chronic pancreatitis presents most commonly with pain – this is severe in nature and often
radiates ‘straight through’ to the back. This may be a chronic unremitting pain or may be episodic.
Anorexia is common in periods of pain and weight loss (possibly extreme) is common.
In the absence of pain, malabsorption, jaundice or diabetes maybe initial presentations.
An important differential is that of carcinoma of the pancreas, which may present in the same
way.
Investigations: (amylase is rarely raised)
 faecal elastase
 Contast enhanced CT
 MRI / MRCP
Treatment:
 Pain control via a mix of NSAIDs and opiates (e.g. Tramadol). Amitryptaline is also used
sometimes where opiate addiction is likely due to duration of pain.
 Food intake boosted to ~150% normal
 Vitamin supplements
 Pancreatic enzyme supplements
 PPI (reduces degradation of enzyme supplements)
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Appreciate the possibility of small bowel disease in patients presenting with different
forms of nutritional anaemia
Some small bowel causes of malabsorption
Coeliac disease
Tropical sprue
Dermatitis
Whipples disease
hepetiformis
Bacterial overgrowth
Radiation enteritis
Intestinal resection
Parasite (eg Giardia)
Coeliac disease: may appear from any age (weaning upwards) with a peak in the fifth
decade. Women are affected more than men. Complications include osteoporosis and anxiety /
depression.
Tropical sprue is a disease of unknown aetiology that is probably infectious – it occurs in
epidemics and can be controlled by antibiotics. Giardia and other acute infection should be
excluded before making this diagnosis. Onset may be acute, days-years after being in the tropics.
If nesesary, resusitate with fluids and electrolytes and correct nutritional deficiencies.
Treatment consists of leaving the sprue area, long term (6 m) antibiotic e.g. tetracycline, folic acid
(5 mg) and B12 (1 mg).
Bacterial overgrowth is a disease in which the almost sterile upper small bowel becomes
colonised by bacteria. This area is normally kept clear by gastric acid and jejunal motility. The
bacteria are typically those inhabiting the terminal ileum – faecal organisms such as E. coli and
Bacteroides.
These bacteria act to deconjugate and dehydroxylate bile acids leading to a malabsorption of
fats (and steatorrhoea). They also metabolise B12 (causing deficiency) and may secrete folate
(levels rise).
Investigation is by the hydrogen breath test and treatment is to correct the underlying
problem that allowed them to colonise the proximal small bowel or to rotate antibiotics if this
cannot be done.
Small bowel resection may be carried out for many purposes – resection of the jejunum is
not serious as the ileum can take over its functions but ileal resection results in the malabsorption
of bile salts and vitamin B12 resulting in a macrocytosis. The entry of excess bile salts and fatty
acids to the colon results in malabsorption of water and electrolytes leading to diarrhoea.
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Explain to patients how small bowel disease is investigated.
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FBC: anaemia
B12 / folate
Iron / TIBC / ferritin
Antibodies: endomysial (EMA) and tissue transglutaminase (tTG) for coeliac
Duodenal / jejunal biopsy: (gold standard for coeliac)
Small bowel follow through
Bone densitometry (osteoporosis in coeliac).
 Explain to patients the rationale for and practical implications of a gluten-free diet.
This may be useful to control either coeliac disease or dermatitis herpetiformis. Both of these
diseases are gluten sensitive. In coeliac disease,
Background box: gluten is found in wheat, rye and barley and is broken down into several
substances called gliandins () that can cause problems in people with a certain genetic
predisposition – there is also an environmental exposure required and it is thought that this may
be viral.
In coeliac disease the enzyme tissue transglutaminase (which modifies gliandins) enhances
gliandin specific T cell response. Antimyosial antibody is also formed against this enzyme.
The result of the autoimmune response is a flattening of the mucosal surface and a loss of
villi. Crypt hyperplasia and an increase in chronic inflammatory cells are also seen. Surface cells
become cuboidal. Damage decreases moving towards the ileum as gluten is further digested.
The person who prepares the patient's food must fully understand the gluten-free diet. Read food
labels carefully.
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Do not eat anything that contains the following grains: wheat, rye, barley, and oats.
The following can be eaten in any amount: corn, potato, rice, soybeans, tapioca,
arrowroot, carob, buckwheat, millet, amaranth and quinoa.
Distilled white vinegar does not contain gluten.
Malt vinegar does contain gluten.
Grains are used in the processing of many ingredients, so it will be necessary to seek out hidden
gluten. The following terms found in food labels may mean that there is gluten in the product.
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Hydrolyzed Vegetable Protein (HVP), unless made from soy or corn
Flour or Cereal products, unless made with pure rice flour, corn flour, potato flour, or soy
flour
Vegetable Protein unless made from soy or corn
Malt or Malt Flavoring unless derived from corn
Modified Starch or Modified Food Starch unless arrowroot, corn, potato, tapioca, waxy
maize, or maize is used
Vegetable Gum unless vegetable gums are carob bean gum, locust bean gum, cellulose
gum, guar gum, gum arabic, gum aracia, gum tragacanth, xanthan gum, or vegetable
starch
Soy Sauce or Soy Sauce Solids unless you know they do not contain wheat
Any of the following words on food labels usually means that a grain containing gluten has been
used
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stabilizer
starch
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flavoring
emulsifier
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hydrolyzed plant
protein
http://www.gicare.com/pated/edtgs06.htm is an excellent site to recommend.